The use of three-dimensional nanostructures to instruct cells to produce extracellular matrix for regenerative medicine strategies

Synthetic polymers or naturally-derived extracellular matrix (ECM) proteins have been used to create tissue engineering scaffolds; however, the need for surface modification in order to achieve polymer biocompatibility and the lack of biomechanical strength of constructs built using proteins alone remain major limitations. To overcome these obstacles, we developed novel hybrid constructs composed of both strong biosynthetic materials and natural human ECM proteins. Taking advantage of the ability of cells to produce their own ECM, human foreskin fibroblasts were grown on silicon-based nanostructures exhibiting various surface topographies that significantly enhanced ECM protein production. After 4 weeks, cell-derived sheets were harvested and histology, immunochemistry, biochemistry and multiphoton imaging revealed the presence of collagens, tropoelastin, fibronectin and glycosaminoglycans. Following decellularization, purified sheet-derived ECM proteins were mixed with poly(?-caprolactone) to create fibrous scaffolds using electrospinning. These hybrid scaffolds exhibited excellent biomechanical properties with fiber and pore sizes that allowed attachment and migration of adipose tissue-derived stem cells. Our study represents an innovative approach to generate strong, non-cytotoxic scaffolds that could have broad applications in tissue regeneration strategies.     

Outcome of orthotopic liver transplantation in patients with haemophilia

Background—Many patients with haemophilia havedeveloped cirrhosis or hepatocellular carcinoma due to transfusionacquired chronic viral hepatitis.
Aims—To assess the long term outcome of allhaemophilic patients reported to have undergone orthotopic liver transplantation.
Methods—Transplant centres of patients identifiedby medical database search were contacted and survival data assessed by Kaplan-Meier analysis.
Results—Twenty six haemophilic men (median age 46 years, range 5-63 years) underwent orthotopic liver transplantation in16centres between 1982 and 1996. Indications for transplantation werehepatitis C cirrhosis (69%), hepatitis B with or without C cirrhosis(15%), viral hepatitis related hepatocellular carcinoma (12%), andbiliary atresia (4%). Six patients (23%) were infected with humanimmunodeficiency virus (HIV). Postoperatively, the median time tonormal clotting factor levels was 24 hours (range 0-48 hours) andexogenous clotting factors were stopped at a median of 24 hours (range0-480 hours). Four patients (15%) had bleeding complications. The oneand three year survival of HIV positive recipients (67% and 23%) wassignificantly poorer (p=0.0003) than that of HIV negative recipients(90% and 83%). Coagulopathy was cured in all patients surviving morethan 12 days post-transplant. Six of the 20 patients (30%) withhepatitis C cirrhosis pretransplant had evidence of disease recurrenceat a mean of nine months post-transplant.
Conclusions—Hepatitis C cirrhosis is the mostcommon indication for orthotopic liver transplantation in patients withhaemophilia. Transplantation results in long term cure of haemophiliabut may be complicated by the effects of HIV infection or recurrentviral hepatitis.

Keywords:liver transplantation; haemophilia; hepatitis C; cirrhosis; HIV

     

A polymorphism of the cholesteryl ester transfer protein gene predicts cardiovascular events in non-smokers in the West of Scotland Coronary Prevention Study.

AIM: The association of cholesteryl ester transfer protein (CETP) gene polymorphisms with risk of a cardiovascular event and whether any association was explained by an influence on high-density lipoprotein (HDL) levels or low-density lipoprotein (LDL) size was tested in the West of Scotland Coronary Prevention Study (WOSCOPS). Gene-smoking and gene-treatment interactions were investigated. METHODS AND RESULTS: Cases (n=498) and controls (n=1108) were typed for TaqIB, C(-631)A, C(-629)A, I405V and D442G CETP polymorphisms. Homozygotes for the TaqIB2 allele (B2B2) had a 30% reduced risk of a cardiovascular event (odds ratio [OR] 0.70, CI(95)0.51-0.96, P=0.03) compared to B1B1 homozygotes. Inclusion of HDL or LDL diameter in multivariate analysis only marginally attenuated the relationships. Non-smokers, but not smokers, showed a dose-dependent association of risk with TaqIB genotype. Treatment benefit was not significantly different in B1B1 (OR 0.71, pravastatin vs placebo), B1B2 (OR 0.68) and B2B2 (OR 0.61) individuals. The other CETP polymorphisms studied had no significant association with cardiovascular risk. Haplotype analysis did not add to the information given by the individual polymorphisms. CONCLUSION: The association between CETP TaqIB genotype and cardiovascular risk is primarily in non-smokers, is not fully explained by effects on HDL levels or LDL size, and the benefit of pravastatin treatment was not influenced by this polymorphism.     

Structure-activity relationships for pyrido-, imidazo-, pyrazolo-, pyrazino-, and pyrrolophenazinecarboxamides as topoisomerase-targeted anticancer agents.

Heterocyclic phenazinecarboxamides were prepared by condensation of aminoheterocycles and 2-halo-3-nitrobenzoic acids, followed by reductive ring closure and amidation. They showed similar inhibition of paired cell lines that underexpressed topo II or overexpressed P-glycoprotein, indicating a non topo II mechanism of cytotoxicity and indifference to P-glycoprotein mediated multidrug resistance. Compounds with a fused five-membered heterocyclic ring were generally less potent than the pyrido[4,3-a]phenazines. A 4-methoxypyrido[4,3-a]phenazine (IC(50)s 2.5-26 nM) gave modest (ca. 5 day) growth delays in H69/P xenografts with oral dosing.     

Penetrating stab wound injuries to the face.

Penetrating knife blade injuries to the maxillofacial region are quite rare, with retained knife blades even rarer. Associated vascular, ocular, ductal, neurosurgical injuries should be identified and treated accordingly. Appropriate special investigations included plain radiographs and angiograms, which were used in establishing the proximity of the foreign object to the arterial supply to the head and neck. The impacted blade should be removed in theatre. Ten patients with this injury are discussed.     

Rotational imaging of complex acetabular fractures: The dynamic judet view

The use of rotational digital subtraction angiography for imaging complex pelvic and acetabular fractures is described, and its advantages are presented.     

Registration and display of the combined bone scan and radiograph in the diagnosis and management of wrist injuries

A system has been developed for the registration and combined display of the X-ray image and isotope bone scan. This system has been evaluated by prospectively studying 23 patients who were referred for suspected injury of the wrist. The registration system has an inherent precision for registration of about 1 mm. When patient positioning errors are included, this increases to about 4 mm. Two observers evaluated the sets of images prior to registration and after registration and combined display. They judged that in 16 out of 17 cases judged abnormal (observer 1) and 12 out of 18 cases judged abnormal (observer 2), the registration technique improved localization of a lesion. One case was rejected as registration was not possible due to incorrect positioning of the hand. Offprint requests to: D.J. Hawkes     

Long-Acting Propranolol in the Prophylaxis of Migraine

SYNOPSIS
A retrospective chart review of 200 patients with headache who had been treated with long-acting propranolol indicated that this agent is as safe and as efficacious as regular propranoIol in the prophylaxis of migraine. Overall, 57% reported good or excellent results. Only 7% had to discontinue treatment because of side effects. Compliance was excellent with the long-acting form.